Large barnacle skeletons in reef tank?

[Swingline77]

I've seen groups of barnacle skeletons for sale in which the individual barnacles are several inches in length. These seem like they'd make great hiding places, but they also seem like they'd create micro areas without flow. Are these a good idea to have in a tank?

 

[justmee]

I have some in my mixed reef tank, and it's my bi-color blenny's home...

 

[Thingsibuild]

My blenny love his also.

 

[Swingline77]

thanks